June 2013

Editor-in-Chief Nils Enlund

JPMTR 017 ⎮ 1305 Technical paper

UDC 655.326.1:676:22

Received: 2013-02-23

Accepted: 2013-06-17

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2-13

 

Influence of surface roughness on print quality on digitally printed self adhesive foils

Dragoljub Novaković1, Mladen Stančić2, Igor Karlović1, Nemanja Kašiković1, Valentina Vukmirović2, Rastko Milošević1

1 University of Novi Sad, Faculty of Technical Science, Department of Graphic Engineering, Novi Sad, Serbia; E-mails: novakd@uns.ac.rs; karlovic@uns.ac.rs;
knemanja@uns.ac.rs; rastko.m@uns.ac.rs

2 University of Banja Luka, Faculty of Technology Department of Graphic Engineering, Banja Luka, Bosnia and Herzegovina; E-mails: Mladen.stancic@unibl.rs; valentina08bl@gmail.com

Abstract

The printing substrate, together with its characteristics, has a significant influence on print quality. The substrate topography, or roughness, is one of the most significant printing substrate factors. Substrates with different topography reflect light in various manner which leads to various print quality. Print quality itself can be defined as a complex term that includes both the desired colour reproduction and a satisfactory reproduction of image elements. In this paper we focus on print quality analysis of ink-jet printed PVC self adhesive substrates. The study includes evaluation of mottle, line quality, dot roundness, print sharpness and colour reproduction. Based on our analysis, it can be concluded that substrate roughness and other parameters, such as colour properties and reverse side printing, have a significant influence on print quality.

Keywords: PVC self adhesive foil roughness, mottle, line quality, dot roundness, print sharpness, colour gamut

JPMTR 016 ⎮ 1216 Research paper

UDC 535.64:681.6

Received: 2013-06-06

Accepted: 2013-07-08

A simple color separation model based on colorimetric and spectral data

Yuanyuan Qu and Sasan Gooran

Department of science and Technology, Linköping University, Campus Norrköping, SE-601 74 Norrköping, Sweden; E-mails: qu.yuanyuan@liu.se; sasgo@itn.liu.se

Abstract

A color separation model which separates a target color inside the gamut of a printing system into the combination of process inks used in the system is a crucial part of the printing procedure. A simple color separation model for CMY printing is presented in this paper. It is based on a color prediction model proposed in our previous papers. This color prediction model, which was based on CIEXYZ (CIELAB) values, is extended in this paper to work also for spectral data. Therefore, the color separation model is executable for target colors represented by both CIELAB and spectral data. Two experiments are designed and carried out to evaluate the accuracy of the proposed models. The first experiment proves the accuracy and stability of the forward (color prediction) model. The second experiment shows that our simple inverse model (color separation) has a satisfying accuracy for different target colors in terms of giving less ink consumption and small CIELAB (ΔE94) or small spectrum difference (ΔRMS). The proposed color separation model has the potential to be applied to practical printing systems due to its simplicity and accuracy.

Keywords: spectral printing, color separation, color prediction, dot gain, effective coverage map

JPMTR 020 ⎮ 1308 Case study

UDC 659.3:054

Received: 2013-05-10

Accepted: 2013-07-19

Interactive and social – A study of Swedish online newspapers

Cecilia Teljas

KTH Royal Institute of Technology, Department of Media Technology and Interaction Design, SE-10044 Stockholm, Sweden; E-mail: teljas@kth.se

Abstract

This study explores how established media services such as online newspapers meet the increasing popularity of social media. A case study of Aftonbladet.se was conducted in order to understand how one of the leading Swedish online newspapers uses social media and relates to this new media form. The most important evidence of the influence of social media on Aftonbladet is apparent in the way its role as an online newspaper is expressed: “Aftonbladet wants to be a meeting place (…). The whole experience builds on interactivity and community”. The case study results of Aftonbladet’s social media use are interesting because they offer indications of Sweden’s leading online newspaper’s take on new media development and more specifically of the reasoning within the newspaper organization around the changing user relations.

Keywords: media, interactivity, media convergence, participation, users

JPMTR 1309 Professional communication

UDC 681.625.838

Received: 2013-06-06

Accepted: 2013-07-22

Comparative analysis of Braille dot parameters using relative integral criteria

Volodymyr Mayik1, Taras Dudok1, Gorazd Golob2, Sabina Bračko2

1 Ukrainian Academy of Printing, Pid Holoskom St. 19, UA-79020 Lviv, Ukraine; E-mails: maik@polygraf.lviv.ua; t.dudok2010@yandex.ua

2 University of Ljubljana, Faculty of Natural Sciences and Engineering, Aškerčeva 12, SI-1000 Ljubljana, Slovenia; E-mails: gorazd.golob@ntf.uni-lj.si;
sabina.bracko@ntf.uni-lj.si

Abstract

Relative integral evaluation criteria for the comparative analysis of the Braille character shape have been suggested based on the fact that there are significant differences in national requirements. A set of Braille character profiles has been built through computer simulation and the impact of the geometrical dimensions of the elements on the integral criteria has been determined. The limit value of the integral evaluation criteria of Braille character shapes has been determined.

Keywords: Braille fonts, mathematic modelling, Braille dot shape, Braille dot dimensions